(define-record-type <voronoi-region>
(make-voronoi-region seed vertices)
voronoi-region?
(seed voronoi-region-seed)
(vertices voronoi-region-vertices))
(define-record-type <voronoi-region>
(make-voronoi-region seed vertices)
voronoi-region?
(seed voronoi-region-seed)
(vertices voronoi-region-vertices))